Method and apparatus for injecting fluids into earth formations penetrated by a well



1 5 5 5 7 wuss wmmm SkARCH RD METHOD AND APDARATUS FOR INJECTING FLUIDS INTO EARTH FORMATIONS PENETRATED BY A WELL I F11ed' Nov. 13, 1964 4 Jan. 9; was r H. @RANDT awaw'i \ACETONE mesa.

RESIN ACTIVATOR INVENTOR HARRY BRANDT United States Patent ABSTRACT OF THE DISCLOSURE The invention is directed to injecting liquid into a packed-off perforation of a well and includes a valve which is sensitive to the pressure differential between the inside of the injection tool and the annulus between the tool and the well bore to assist in controlling the flow of the liquid.

This invention relates to apparatus useful to inject fluids into earth formations penetrated by a well and, more particularly, this invention relates to apparatus for use in consolidating unconsolidated sand Surrounding oil or gas or injection wells by means of injecting into the formation predeterminable amounts of consolidation liquids.

In oil recovery operations and particularly in oil well completion and recompletion work it is often necessary to practice sand control, i.e., to prevent or greatly reduce flow of sand into a well. Sand control has heretofore been practiced by a number of methods. For exam ple. gravel or sand packing of the space between a perforated well casing and the production tubing has been done to deter the flow of sand into the production tubing. Prepacked sand control liners have also been connected to production tubing and inserted into wells and positioned adjacent a producing formation to assist in preventing sand flow up the tubing. More recently, methods have been devised to consolidate formation sand in place around the well by injecting a liquid binding material into the formation to contact the loose sand and to consolidate it when the binding material hardens.

- ,'When the last-mentioned sand consolidation process is used in actual practice it is necessary that the sand consolidation liquids be injected uniformly around the well in the formation interval which is to be consolidated. The formation interval where Consolidation by this method is to be done may be a thick section made up of a number of intervals or portions having different permeabilities.

' The consolidation liquids, of which usually there are at least two, typically have different viscosities. Thus when it is desired to consolidate a permeable interval of a formation, it is a difficult problem to provide for even distribution of a consolidation liquid in the formation around the well over the entire interval.

"As is known in the petroleum producing art, a casing is usually used to line a producing interval or an injection'interval. Spaced over the length of the casin g opposite the selected interval are perforations through which oil can flow into the casing from the formation or through which water can flow from the casing into the formation. Usually, the distance between perforations in the casing opposite a particular producing interval is a foot or less. In wells which penetrated a number of producing intervals a number of groups of perforations may exist spaced at appropriate intervals in the casing. Since as discussed above, the formation behind the various perforations may not be of uniform permeability, the sand consolidation liquids that are injected into the formation through any group of perforations will not necessarily be distributed uniformly in the formation around the well unless the injection is carefully controlled. It is a difficult problem to obtain even distribution of injected liquids through the perforations in the casing over the selected interval to be consolidated.

Various forms of apparatus for accomplishing uniform injection of a variety of fluids into a producing formation to consolidate sand have been suggested. However, there is still need for apparatus for use in sand consolidation which is simple in construction and reliable in operation and which will permit the uniform injection of fluids at high pressure over a selected interval of a formation without danger of fracturing the formation or damaging the apparatus should plugging and pressure build-up occur in the well or in the formation.

In one aspect the present invention provides apparatus for sand consolidation including a central tubular member insertable into a Well and tubing means for forming a flow path between the central tubular member and the surface. A plurality of packing means are provided to pack off selected portions of the well casing outside of the said central tubular member. At least one perforation of the well casing is packed off in each of the selected portions. A plurality of restricted passageway means are formed through the tubular member at selected intervals to cooperate with the packing means and to provide communication between the perforations in each packed-off portion and the interior of the tubular member. The restricted passageway means act in a manner similar to a critical fiow orifice in that they maintain liquid flow therethrough at a relatively constant rate at pressure above a predeterminable minimum pressure. Check valve means are provided in each restricted passageway means. The

check valve means preferably initially'close the restricted passageways to fluid flow and have resilient means to normally retain the check valve means in closed position. Each check valve means is responsive to pressure increase in each of the packed-off portions of the casing and will throttle flow or even close in the event of an undesirably high pressure build-up in the packed-off portion of the casing outside the tool indicating plugging of the perforation or of the formation before damage is done to the formation.

It is a particular object of this invention to provide improved apparatus for injecting fluid at uniform rates into a plurality of spaced apart perforations in a well casing while eliminating the chance of fracturing the formation or otherwise damaging the well by undesirably high pressure resulting from the formation not accepting the fluid at the desired rate.

Further objects and advantages of the present invention will become apparent from the following detailed description read in light of the accompanying drawing which is a part of this specification and in which:

FIGURE 1 is a view partially in section of a well penetrating an earth formation and illustrates apparatus assembled in accordance with the present invent'on;

FIGURE 2 is a sectional view showing a portion of the preferred embodiment of apparatus assembled in accordance with the present invention;

FIGURE 3 is a front elevation taken at line 3--3 of FIGURE 2.

Referring now to the drawings, and to FIGURE 1 in particular, the apparatus of the present invention will be described in detail. The apparatus assembled in accordance with the present invention is shown located in a well 20 adjacent the formation 21 into which the consolidated liquids are to be'injected. A well casing 22 is used to line the wall of well 20. Cement, or other suitable grout 23, is used to seal the annular space between the well wall and the outside of the casing 22. A number of perforations 24 have been made in the casing 22 and extend through the grout 23 and into the formation 21. These perforations 24 may be made by suitable perforating means. For example, gun perforating is a suitable technique, well known in the art, for providing perforations in a well casing.

flow. A tubing string 27 is connected in a fluid-tight manner to the upper end 28 of the tubular member 25 by suitable means such as adapter sub 19. The tubing string 27 extends up the well and provides a flow path from the surface to the interior of the tubular member 25. Suitable sources of sand consolidation liquids such as resin source 29, acetone source 30, activator source 31 and diesel source 32 are connected through pump 34 and the tubing string 27 to the tubular member 25. In regard to the above listed sources of liquids however it is pointed out that the materials or techniques of a particular sand consolidation operation are not controlling the invention. However it is highly desirable to use material sources located on the surface and connected to the tubular member 25 by tubing since this permits use of large quantities of material in no way limited by space requirements as if, for example, the sources were located in the well.

The tubular member 25 is provided with a plurality of pack-E means 33 which pack off portions of the annular space between the well casing 22 and the outside wall of the tubular member at a plurality spaced apart locations. It is contemplated that the pack-01f means of the present invention will be arranged to pack off one or more of 'a plurality of perforations 25. Thus a plurality of annular chambers are formed to each provide communication from the interior of the tubular member with one or more of the perforations. The packing means 33 are only schematically represented in FIGURE 1 and they may be of any suitable construction and may be activated mechanically or hydraulically or by any other suitable means well known in the art. For example, suitable hydraulic packers include the hydrostatic packer illustrated on page 516 of the 26th (1964-65) Revision of the Composite Catalog of Oil Field'Equipment and Service. Another example of a suitable hydraulically set packer is illustrated on page 866 of the 29th (1962-63) Revision of the Composite Catalog.

Means forming restricted passageways having check valve :meansformed therein are provided to allow communication between the tubular member 25 and each of I the packed-off perforations. These means are generally indicated by the numeral 35. The means forming a restricted passagewayand the check valve means are housed together in a common removable housing member 36. With reference to FIGURES 2 and 3 these means will be described in greater detail.

A housing member 36 is, provided to contain the restricted passageway and the check valve means. The housing member 36 is removably connected in the tubular member 25 as by mating threads 60 and 61. A suitable restricted passageway means may include flow paths 40 and 42 and an orifice insert 41 which has a restricted opening 46. A check valve seat 43 having an opening 44 therethrough'completes the passageway. The flow paths and inserts are providedwith easy access for cleaning purposes. For example the inserts 41 and 43 are removable and one end of flow path 42 is closed by means of removable plug45. The inserts, housing members and plugs are provided with suitable grooves 65 to allow easy removal and insertion. The grooves 65 are cut only deep enough into the members to permit engagement by a key.

In accordance with the present invention a check valve means is provided is the restricted passageway. For example,ja check valve stem is normally urged into valve seat 43 by means of a suitably arranged spring 51 to close the passageway. The upper end 52 of valve stem 50 is formed in a piston like manner and fits in fluid-tight slideable relationship in chamber 54. A back plate 55 acts to Iseat spring 51. An opening 56 in the back plate allows pressure on the outside of the apparatus to act on the piston end of the valve stem. The piston member is also &

sensitive to pressure inside the tubular member 25 since port 57 allows communication between the piston and the fluid in the tubular member 25. Thus when the pressure on the liquid inside the apparatus is greater than the pressure outside the tubular member plus the force of the spring 511 the check valve is open and fluid can flow through the restricted passageway. However if the action of the pressure outside the tool and the spring force become greater than the action of the pressure inside the tool, the check valve closes and no fluid can flow through the restricted passageway. This condition will continue until the pressure outside the tubular member falls below some given pressure differential below the inside pressure when flow can again resume. Thus the check valve means of the present invention acts to throttle flow when pressure build-up occurs.

As indicated above there is a problem in getting each of the perforations to take an equal amount of the consolidation liquids. This is illustrated graphically in FIG- URE 1 by a relative shading of the formation to indicate zones of greater and lesser permeability. Thus a perforation which extends into a zone of high permeability would probably take more of the consolidation liquid than one into a zone of lesser permeability if the consolidation liquid were flowed in the perforations without some kind of control.

The restricted passageways are used to assist in accomplishing equal or nearly equal distribution of the consolidation liquids to the formation. Thus when a compressible fluid is pumped through an orifice at a constant upstream pressure there is a pressure diflerence across the orifice at which maximum flow occurs and even if the downstream pressure decreases so that the pressure difference becomes greater than the critical pressure diflerence no more flow occurs. The consolidation liquids will react in somewhat a similar manner when flowing through the restricted passageway. Thus the passageways are sized so that only a predetermined amount of flow can take place through each passageway after a certain pressure differential bewteen the inside and outside of the tubular member is reached. However if the pressure outside the tubular member builds up to undesirably high values because the formation does not take the fluids, the check valve means throttles flow and eventually shuts off flow through the restricted passageway.

The liquid flowing through the plurality of passageway is thus flow-regulated and even though one of the perforations might have the capacity to take the consolidation liquids at a much higher rate than the perforations in another packed-otl portion, that perforation will receive the predetermined amount of consolidation liquid since each perforation is packed off and the flow to each packed-off portion is regulated. This is true so long as the perforation taking liquid at the slowest rate is capable of taking the liquid at a rate faster than the rate of the liquid flow through the restricted passageway. In most formations this will be the case. However if for some reason, such as a very tight portion of a formation or plugging of a perforation, the fluid is not taken by the formation at at least this minimum rate pressure build-up in the annulus can occur. The increased pressure can result in fracture of the formation. If pressure build-up reaches an undesirably high level the check valve means of the present invention reacts as heretofore described to close the particular passageway to the flow of liquid thus preventing damage to the formation. When the pressure has dropped to a safe level the check valve opens and flow resumes. As is evident the strength of the check valve spring can be changed to vary the differential pressure required to close the check valve. It is contemplated that good engineering practice can determine the desirable diiferential pressure for any given operation knowing the fracture pressure of the formation, the strength of the tool and other factors.

It is apparent that modifications other than those described herein may be made to the apparatus of this invention without departing from the inventive concept. It is also apparent that the use of the present apparatus is not limited only to sand consolidation. For example, in well stimulation, solvents, acids or other stimulation fluids are sometimes injected into a producing formation to increase the flow capacity of the formation. It is evident that unition in a well casing adjacent a formation penetrated by a well comprising a tubular member insertable into a well, packing means on said tubular member for packing oil? a portion of the well to form a flow chamber adjacent a selected perforation, flow passageway means in said tubular member to provide communication between the in- .terior of said tubular member and said flow chamber,

check valve chamber means on said tubular member, means movable in said check valve chamber means and extendable into said flow passageway means for controlling fluid flow through said fluid passageway means, resilient means for urging said means movable to a position to close said passageway means, independent fluid communication means providing independent fluid communication between said flow chamber and said check valve chamber means and piston means in said check valve chamber means to cause the fluid in said flow chamber to act in cooperation with said resilient means to urge said means movable into said restricted passageway means to restrict flow therethrough as the pressure in said flow chamber increases above a predeterminable value.

2. Apparatus for use in injecting fluids into a plurality of spaced-apart perforations in a well casing comprising a'tubular member insertable into a well, packing means on said tubular member for packing otf portions of the annular space between said tubular member and the well casing at selected intervals to form flow chambers adjacent selected perforations, flow passageway means in said tubular member to provide communication between the interior of said tubular member and each of said flow chambers, check valve chamber means on said tubular member adjacent each of said flow passageway means, means movable in each of said check valve chamber means and extendable into each of said flow passageway means for closing each of said fluid passageway means, resilient means urging each of said means movable to a position to close each of said passageway means, independent fluid communication means providing independent fluid communication between each of said flow chambers and each of said check valve chamber means and piston means in each of said check valve chamber means to cause the fluid in each of said flow chambers to act in cooperation with said each of said resilient means to urge each said means movable into each of said restricted passageway means to-restrict flow therethrough.

3. Apparatus for use in injecting fluids into a plurality of spaced apart perforations in a well casing comprising a tubular member insertable into a well, well tubing connected to said tubular member to form a flow path between said tubular member and the surface, a plurality of spaced apart packing means on the outside of said tubular member packing off portions of the space between said tubular member and the well casing at selected intervals to isolate selected perforations in the casing from each other, restricted passageway means in said tubular member cooperating with each of said packed-off portions to provide fluid flow paths from the interior of said tubular member to each of said selected perforations and check valve means on each of said restricted passageway means, each of said check valve means comprising a stem extend- 1 ible into said restricted passageway means to close said I passageway means, resilient means urging said stem into said passageway means, piston means connected to said stem and fluid communication means communicating with said piston means in the packed-off portions outside said tubular member to assist to urge said stem into said passageway means.

4. Apparatus for use in injecting fluids into a plurality of spaced apart perforations in a well casing comprising a tubular member insertable into a well, well tubing connected to said tubular member to form a flow path between said tubular member and the surface, a plurality of spaced apart packing means on the outside of said tubular member packing off portions of the space between said tubular member and the well casing at selected intervals to isolate selected perforations in the casing from each other, restricted passageway means in said tubular member cooperating with each of said packed-off portions to provide fluid flow paths from the interior of said tubular member to each. of said selected perforations and check valve means on each of said restricted passageway means,

each of said check valve means comprising a stem extendible into said restricted passageway means to close said passageway means, piston means connected to said stern and fluid communication means communicating with said piston means and the packed oif portions outside said tubular member to urge said stem into said passageway means.

5. Apparatus as in claim 4 further characterized in that each restricted passageway means and check valve means is in a unitary housing which housing is removably secured in said tubular member.

6. A method of injecting liquid into an earth formation penetrated by a well comprising the steps of inserting a tubular member into a well and positioning said tubular member adjacent a selected formation penetrated by said well, packing off at least a portion of the space in said well between said formation and said tubular member to form a flow chamber isolated from the rest of said well, initially resiliently closing a flow passageway between the interior of said tubular member and said flow chamber, forcing liquid in said tubular member to open said flow passageway and flow into said flow chamber and into said formation and flowing a portion of said liquid to a position back into said tubular member but out of the main flow path of said tubular member to assist in closing said flow passageway to control the flow of liquid into said flow chamber as the pressure in said flow chamber increases above a predeterminable value while continuing to force liquid to flow into said flow chamber. I

'7. A method of injecting liquid into an earth formation penetrated by a cased well having a penetration adjacent said formation comprising the steps of inserting a tubular member into a cased well and positioning at least a portion of said tubular member adjacent a selected perforation in said well, packing off at least a portion of the annular space adjacent said perforation in said well between the casing and said tubular member to form a flow chamber isolated from the rest of said well, initially resiliently closing a flow passageway between the interior of said tubular member and said flow chamber, forcing liquid in said tubular member to open said flow passageway and flow through said flow chamber and into said formation and flowing a portion of said liquid to a position back into said tubular member but out of the main flow path of said tubular member to assist in closing said flow passageway to control the flow of liquid into said flow chamber while continuing to force liquid to flow into said flow chamber.

8. The method of claim 7 further characterized by the step of stopping liquid flow into said flow chamber in response to a predcterminable pressure increase in said chamber.

9. A method of injecting liquid into an earth formation penetrated by a cased well having a plurality of penetrations adjacent said formation comprising the steps of inserting a tubular member into a well and positioning said tubular member adjacent selected perforations in said well, packing off at least a portion of the annular space adjacent each of said perforations in said well between said casing and said tubular member to form a flow chamber isolated from the rest of said well at each perforation, initially resiliently closing a flow passageway between the interior of said tubular member and each of said flow chambers, forcin g liquid in said tubular member to open each of said flow passageways and to flow through each of said flow chambers and into said formation and flowing a portion of said liquid to a position 'back into said tubular member but out of the main flow path of said tubular member to assist in closing each of said flow passageways to control the flow of liquid into each of said flow chamhers while continuing to force liquid to flow into said flow chambers.

References Cited UNITED STATES PATENTS 1,927,958 9/ 1933 Simmons. 1,939,630 12/1933 Pauly 137503 X 2,107,006 2/1938 Lang 166-10 X 2,361,194 10/1944 Grebe 166-.-186 X 2,611,436 9/1952 Carr et a1 166--10 X 2,643,208 6/1953 Ogden et a1. 166--10 X 2,973,039 2/ 1961 Payne.

10 3,022,829 2/1962 Hodges 166224 ERNEST R. PURSER, Primary Examiner.

I. A. CALVERT, Assistant Examiner. 

